Just defeated the game 100%. Took about 64 hours total, but a couple of the hours were from me getting up and doing something.
All in all, I thought the game was a stunning. The item location, while bothersome at times, I found to be extremely fun. The combat with the characters didn't disappoint either.
I found all the boss battles to be very enjoyable, and every character was useful in their own way. Robin was especially useful in travelling and collecting items. Nami helped me steal a lot of items as well.
I found most of the bosses easy, but it was still fun whooping them. Kaku surprisingly, wound out being the easiest for me, the second go round. The hardest was Whitebeard, followed by Shanks.
Rampaging Chopper was tough, but all he has is defense. If you can stay away from him, he's a walk in the park. Similar things can be said for Aokiji. Lucci was tough cookie, but I managed to Gigant Pistol him both times.
Crocodile was tough as well, his special is killer. Ace and the aforementioned Aokiji, were surprisingly simple. Paulie and Bon Clay were surprisingly tough. I figured Mihawk and Smoker would be a little bit tougher than they were, but it was all good. Krieg was fairly simple to beat, as expected. Calgara also wasn't too tough.
Evil Guardian I solo'd with Robin. Then the Evil Master Beast was tough. It took me two tries to beat him.
I hate using Mihawk in Vs. Mode, he kind of sucks in Vs. Mode, or maybe I just can't get his style. The best is Rob Lucci, human form. He is 3 points worth of steal, and an absolute beast. I got a perfect against Whitebeard with him on Normal Difficulty.
The Golden Whale wasn't too hard to catch. In fact, fishing itself was fairly easily after I got the controls down. Catching bugs was much tougher, but all in all, I managed to catch every bug in the game, with little difficulty.
I found that it was easier to swing horizontally with bugs on flowers, with one exception. It was much easier to swing downwards on bugs in Dimension Zone. Making healing and stamina powder was pretty simple as well. I also found away to avoid a lot of battles with fodder marines and robots, by running outside of their trigger zone.
Robin and Zoro were best for travelling. Usopp and Luffy were best for fighting.
Now I'm waiting for my friend to get home so we can play some Vs. Mode on two player, so I can solo him with Lucci.
All in all, I loved this game's mixture of Kingdom Hearts and Legend of Zelda.